1. Field
The present disclosure relates generally to aircraft and, in particular, to structures in an aircraft. Still more particularly, the present disclosure relates to a vibration reduction system using a washer in an aircraft.
2. Background
Vibrations are mechanical oscillations that occur in a structure. These oscillations may have one or more different frequencies and directions.
Oftentimes, vibrations are undesirable in a structure. For example, vibrations may waste energy, cause unwanted sound, prevent the structure from operating properly, cause undesired structural changes, and/or result in unwanted motion. For example, vibrations in engines, electric motors, electronic equipment, and mechanical structures that are in operation are typically undesired.
Vibrations may be caused by various sources. Vibrations, for example, may be generated by a motor, the meshing of gear teeth, rotation of aircraft rotors, and other sources. These vibrations may result in decreased efficiency in these devices. The devices may not be able to operate at desired speeds because of the vibrations or may require increased maintenance.
In an aircraft, different moving parts cause vibrations that may travel through different structures in the aircraft. For example, different rotating structures, such as rotor shafts, blades of propellers, and other types of components may cause vibrations or may be affected by vibrations.
Vibrations may be controlled through various vibration reduction systems placed in the path of the traveling vibrations. For example, a vibration may be reduced through a vibration system in the form of a damper or shock absorber. A damper is a mechanical device designed to reduce vibrations by dissipating kinetic energy. This type of device may reduce the oscillations that occur in a structure. The damper may be a shock absorber connected to two components in an aircraft.
For example, dampers may be used in landing gear, seat mounts, engine mounts, and other types of components in an aircraft. Adding dampers or other types of vibration reduction systems may involve adding components that may weigh more than desired, take up more space than desired, and/or cause undesired relative motion between the components in the aircraft. Additionally, the systems may increase the cost and complexity of an aircraft in a manner that is undesired.
Vibrations traveling through an aircraft also may be reduced by modifying the source of the vibrations in a manner to reduce vibrations generated by the source. For example, changes to engine design, blades, and other structures that move may be used to reduce vibrations in an aircraft.
Changing the design of various components to reduce vibrations in an aircraft may require time and expenses that are undesirable. For example, in redesigning blades for an aircraft, the aircraft may be placed into maintenance such that blades may be modified or replaced for the aircraft. This type of vibration reduction takes the aircraft out of use for some period of time. This unavailability of aircraft may be undesirable.
Therefore, it would be advantageous to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.